Electromagnetically controllable fluid propellant type rocket motor system



May 30, 1961 1 Q MCKENNEY 2,986,004

LECTROMAGNETICALLY CONTROLLABLE FLUID PROPELLANT TYPE ROCKET MOTOR SYSTEM Filed June 30, 1958 2 Sheeas-Sheel'l 1 FELl PRESSURE REGULATORN` May 30, 1961 .1. D. MCKENNEY 2,986,004

ELECTROMAGNETICALLY coNTRoLLABLE FLUID PROPELLANT TYPE ROCKET MOTOR SYSTEM Filed June 30, 1958 2 Sheets-Sheet 2 `proportional to the value of an electric United States latent` i ELECTROMAGNETICALLY CONTROLLABLE FLUID PROPELLANT TYPE ROCKET M- TOR SYSTEM John D. McKenney, Newport Beach, Calif., assignor to Clary Corporation, San Gabriel, Calif., a corporation of California Filed June 30, 1958, Ser. No. 745,666

5 Claims. (Cl. 60-35.6)

This invention relates to rocket motors and has particular reference to rocket motors of the liquid, monopropellant type.

The application of rocket motors of the above type `for such purposes as to maneuver or propel a vehicle, space satellite, or the like, generally requires a suitable l control instrumentality whereby the thrust of the motor may be adjustably controlled as desired, either from a point adjacent the motor or from a point remote thererom.

The control of the thrust of rocket motors of the fluid type presents certain problems which have heretofore Y been solved only by the employment of rather highly complex, and in many cases unreliable, systems. For example, one factor affecting the thrust characteristics of such a motor is the supply-pressure of the lluid propellant which is generally contained in a storage reservoir under It thereforebecoms a principal object of the present invention to provide a control mechanism for variably `controlling theY thrust of a rocket motor of the above v type.

Another object is to provide a variable thrust control I system for rocket motors of the above type which is siml ple and effective in operation. A Y

A further object is to provide an electrically controlled v variable thrust control system for rocket motors of the above type wherein the thrust of the rocket is directly control signal applied thereto. y V f The manner in which the above and other objects of 11, for storing the liquid propellant under pressure, a pressure regulator 12, a line shut-olf valve 13, a reaction or decomposition unit 14 and a propellant injector valve l5 forming an injector.

The propellant chosen for the present disclosure of the mono-propellant type commonly known as 'hydraythe invention are accomplished will be readily understood on reference to the following specification when read in rprises a propellant accumulator, generally indicated at ice zine (NaI-I4). However, other types of liquid monopropellant fuels may be used with obvious modifications of the system as dictated by the characteristics of the propellant.

The accumulator 11 comprises a cylindrical shell which is divided by -a sliding piston 16. A sealing ring 17 is located in a groove formed around the periphery of the pistonl to slideably seal the accumulator into two separate chambers 18 and 20. The liquid propellant is 1ocated in the left hand chamber 18 and an inert gas, such as nitrogen, is introduced under a relatively high pressure into the right hand chamber 20. The chamber 18 of the accumulator isA connected by a line 21 to the inlet of the pressure regulator 12.

y Referring to Fig. 3, the pressure regulator 12 comprise y a valve body 22 having an inlet port 23 connected to the line 2'1 and an outlet port 24. The ports 23 and 24 are connected by a passage forming a valve seat 25 which cooperates with a valve element 26 adapted to control the ow of propellant through the regulator. The valve element 26 is slideable endwise and is urge by a relatively light compression spring 27 against a pisy ton 28 slideably Vmounted in /a piston chamber formed inthe valve body 22. A compression spring 30, relatively stronger than spring 27, is interposed between the piston A28 and a cap 31 threaded onto the valve body 22 to enclosed shut-otf valve 13. The valve 13 has an outlet port 34 connected to the inlet port 33 by a passage forming 'a valve seat 35. The latter cooperates with a valve element 36 slideable longitudinally in a bore formed in the body of the valve. A compression spring 37 normally holds the valve element against its seat 35 to thereby close the valve.

A solenoid coil 38 cooperates with an armature 40 engaging the lower end of the valve element 36 so that when the coil is energized, the armature will raise the valve element to thereby establish communication between the inlet and outlet ports.

The decomposition unit 14, forming a reaction charnber, comprises a cylindrical ceramic shell 41 terminating in an exhaust nozzle 42. At its inner end, the shell 41 is closed by an annular ceramic disk 142 embedded in the forward wall of the body 43 of the injector valve 15. Thelatter is preferably formed of aluminum or similar material having high heat conductivity characteristics.

The shell 41 is attached to the body 43 by a anged nut 44' which is threaded on the valve body and engages a ange 45 formed on the inner end of theshell 41'. Y

A valve pintle 46 is slideably mounted in a bore extendingthrough the valve body A43 and opening into the inner end of the shell 41. The pintle has a section 47 of reduced diameter terminating in a conical headv 48 which normally engages a valve seat 50 formed in the valve body 43.

The valve head 48 is effective, when the pintle is moved to the right, to direct the propellant onto a conical screen 51. 'Ihe latter defines a gas generating chamber 49 and also serves to retain a catalyst bed 52 within the shell 41. At relatively high flow rates Ithe valve head atomizes the propellant to spray the same outwardly in all directions against the screen 51. Y

In this disclosure, the catalyst comprises particles of aluminum oxide which are treated with the proper combination of metallic salts. At the rear of the shell 471,

the catalyst is retained by screen 149. j

A heating coil 53 is wrapped around the shell 41 to permit initial heating of the catalyst bed to the proper teur 472,-across the Ycurrent source 71.

Yperature to initiate spontaneous reaction of the propellant as the latter-is sprayed onto the-catalyst. Thecoil is enclosed in a protective sleeve 54 of heat insulating material.

^Af line 55 communicates `the-ou`tlet-port 34 'ofthe `sh11ttvalveulS with Yan inletpassagei 56 opening-into the 'pintle bore `adjacent thel reduced diameterlpintlesecton 47. A second line 57 communicates theY piston chamber l of lthe pressure regulatorlZ (Fig. 3) Vwith a passage 58 opening intothe gas generating chamber* 49of 4the reacf tion unit-whereby to communicate the reaction pressure within the shell 41V to the piston 28 of the pressure regulator.

The pintle 46 is operated by anelectromagnetic actuator, generally `indicated at-60. The latter comprises \anarmature 61'of a material having a high magnetic ypermeability and lowmagnetic retentivity, `on `which is wound an armature coil 62. -The armature is pivotally supported at 63' and is-located in the lield of a permanent t magnet, the -pole pieces of which are shown-at64and 65.

An arm `66`attached tothe armature 61 is connected through a pin and slot couplingl67 to the pintle 46. When the coil 62 is energized, it will effect a clockwise movement of the armature against the action of a tension -spring 68 extending betweenthe pintle 46 and the frame of the actuator, whereby to move the pintle to the right. The characteristics of the-actuator 60 are such that the resultant propellant flow area eected by the pintle valve Ihead 48 is directly proportional to the amplitude of the current 'applied to thearmature coil- 62. This Vis preferably obtained by forming the conical valve surface of the Referring to Fig. 5, the armature coil 62 is connected Vin series -wilh a rheostat`7d, a source of :direct current potential 71 and the coil of a relay 72. The solenoid coil 38 (see also Fig. 4) of the shut-off valve 13 is connected in series `with `normally open contacts 73 of the relay Accordingly, when the rheostat is positioned to effect a flow of `current through the coil `62 to actuate 4the valve pintle 46 to `any open position, the relay 7,2 will be-energized to complete a circuit through the solenoid coil'38 and thus lfully open the shut-olf valve 13.

Describing the operation ofthe system, since in the normal state of` rest of the motor, the valve 13 is closed andno pressure exists in the decomposition chamber, the downstream pressure developed in the outlet portf24fof the pressure regulator is suflicient to actuate the regulator piston 28 to the right to close the regulator valve 26.

/Prior to operating the rheostat 70 to initiate operation of the motor, the chamber heating coil 53 is-caused to heat the catalyst bed 52,-which inlpractice'must be heated to approximately 500 to effect catalytic decomposition of the propellant.

When the rheostat is actuated to Yenergize the armature coil 62, the relay 72 will become energized to open valve 13, thereby reducing the pressure in the outlet port` 24 of the regulator valve. This drop` in pressure will permit spring 30to open the regulator valve, in

the absence of pressure in the decomposition chamber, sufficiently to permit an initial injection of the propellant into the decompositionchamber.

As the propellant decomposes in the chamber todevelop a thrust in the exhaust nozzle 42, pressure 'built uptherein is transmittedthrough the line 57-to the regu- Alator piston 28, causing the same tofurther open the position of the propellant and therefore it will be effective totmaintain a constant differential between'the pressure in the decomposition chamber and the pressure in the inlet passage 56. This will result in a thrustv at the" exhaust i `nozzle-which `-is substantiallydirectly-proportional to the voltage applied to the coil 62 of the electromagnetic actuator,

Although I have described my invention in detail in its preferred embodiment yand have therefore utilized certain terms and language herein, it is to be understood thatv thepresent disclosure is illustrative rather than Yrestrictive andthat changes and modifications may be resorted to without departing from the spirit or scope of the claims appended'hereto.

Having thus described theinvention, 'whatl desire to secure by United States Letters Patent is:

l. Apparatus for introducing a liquid propellant into the reaction chamber of a 'thermal motor comprising a propellant injector communicating `with said reaction chamber, electromagnetic means for controlling said injector to vary the cross sectional area of propellant ow *therethrough into said reaction-r chamber in .proportion `to thefvalue of'electricalenergyappliedto said electromagnetic means, a circuit for applying variableelectrical encrgy'to'said electromagnetic means,` a containerofpropellant under pressure; said pressure varying as' said ptopellant Vis withdrawn from said container, conduit means for conveying said propellantV from said container tof said injector, a pressure regulator in said conduit means, and `means'responsive to 'the pressure in` said reactionchamber for controlling said pressure regulator to provide acon- -stant diierential between the'pressure in the injector inlet andA in said reaction chamber, l

2. Apparatus for introducing-a `liquid propellant -into Ythe reaction chamberof aV thermal motor comprising 'a propellant Yinjector communicating with said reaction place said yvalve device an-amountproportional toI the amount ofelectrical Yenergy Vapplied to said electromag- -netic means, vanelectric circuit `for applying variable 40Au electrical `energy to l-said "electromagnetic means,-said electromagnetic means and said valve device being so arranged that the cross sectional area of propellantl-ow controlled by said -valve device is directly proportional -to thevalue of ielectricalenergy applied to said electromagnetic means, a container of propellant under pressure,

fsaid'pressurevarying assaidpropellant is withdrawn 'from said container, conduit means for conveyinglsaid propellant from said container toA saidinjector, la: pressure Iregulator in said conduit means, and `means responsive to the pressure in said reaction chamber for `controllingsaidfpressure regulator to provide acon'stant chamber, said'injector including a displaceable valve `device; electromagnetic means for displacing said valve device, -a circuitforf-applying variableA electrical energyf-to said electromagnetic means,said electromagnetic means -and`said valve device vbeing so arranged that `the cross 'sectionalarea of propellant tlow controlled by saidivalve device is proportional to the value of `electrical energy applied tolsaid electromagnetic means, a container of propellant under-pressure, said pressure varying .as :said propellant is withdrawn from said container, conduit meanslfor conveying said Vpropellantfrom said i container to said injector, a pressure Iregulator in said conduit "means, `said 'pressure regulator including a aregulating chamber, fa movable chamber closure member insaid regulating chamber, -a valve operable 4by said 'closure "member, said`I valvebeingV in` the' path of flow I of propellant insaid'conduit meansga second conduit means between the .downstream side of said valve' andisaid'regulatingl chamberon one sideof said"closuretmember,

and a third conduit means between said regulating chamber on the opposite side of said closure member and said reaction chamber, said valve and said closure member being so proportioned as to maintain a constant differential between the pressure in the injector inlet and in said reaction chamber.

4. Apparatus for introducing a liquid propellant into the reaction chamber of a thermal motor comprising a propellant injector communicating with said reaction chamber, said injector including a displaceable valve device; electromagnetic means for displacing said valve device, said electromagnetic means and said valve device being so arranged that the propellant flow area controlled by said valve device is directly proportional to the value of electrical energy applied to said electromagnetic means, a circuit for applying variable electrical energy to said electromagnetic means, a container of propellant under pressure, said pressure varying as said propellant is withdrawn from said container, conduit means for conveying said propellant from said container to said injector, a pressure regulator in said conduit means, mans responsive to the pressure in said reaction chamber for controlling said pressure regulator to provide a constant dierential between the pressure in the injector inlet and in said reaction chamber, a normally closed valve in said conduit means, and means responsive to operation of said electromagnetic means for opening said valve.

5. Apparatus for introducing a liquid propellant into the reaction chamber of a thermal motor comprising a propellant injector communicating with said reaction chamber, electromagnetic means for controlling said injector to inject said propellant into said chamber at a rate of ow directly proportional to the value of electrical energy applied to said electromagnetic means, a circuit for applying variable electrical energy to said electromagnetic means, a container of propellant under pressure, said pressure varying as said propellant is withdrawn from said container, conduit means for conveying said propellant from said container to said injector, a pressure regulator in said conduit means, means responsive to the pressure in said reaction chamber for controlling said pressure regulator to provide a constant dierential between the pressure in the injector inlet and in said reaction chamber, a normally closed valve in said conduit means, a second electromagnetic means for opening said valve, and means responsive to application of electrical energy to said rst electromagnetic means for energizing said second electromagnetic means.

References Cited in the le of this patent UNITED STATES PATENTS 2,532,711 Goddard Dec. 5, 1950 2,623,354 Best Dec. 30, 1952 2,644,513 Mock July 7, 1953 2,648,190 Maisner Aug. 11, 1953 2,827,762 Towns Mar. 25, 1958 2,884,009 Hetherington Apr. 28, 1959 FOREIGN PATENTS 719,946 Great Britain Dec. 8, 1954 

